In my ideal world, it would be possible to install all of the necessities for decent Haskell development via a single short command line. I can see two ways to do this:

Create a "haskell-devel" (or something) package that simply depends on all of the Haskell Platform's component packages. This would have the nice property of being versioned, just as the Haskell Platform itself is.

Create a "Haskell Development" group in comps. This is unknown territory to me: I don't know if it's a good idea, how it would work, how I'd edit it to add new dependencies when the Haskell Platform gets updates, or ... well, anything.